Advantage of suppressed non-Langevin recombination in low mobility organic solar cells

Journal Publication ResearchOnline@JCU
Stolterfoht, Martin;Philippa, Bronson;Armin, Ardalan;Pandey, Ajay K.;White, Ronald D.;Burn, Paul L.;Meredith, Paul;Pivrikas, Almantas
Abstract

Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC71BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersive transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.

Journal

Applied Physics Letters

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Volume

105

ISBN/ISSN

1077-3118

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Issue

1

Pages Count

5

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Publisher

American Institute of Physics

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EISSN

N/A

DOI

10.1063/1.4887316